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C Hammerberg

Publications and source records attributed to C Hammerberg.

At least 37 records · Page 2Linked to original sources
PubMed1994

Distinction of class II MHC+ Langerhans cell-like interstitial dendritic antigen-presenting cells in murine dermis from dermal macrophages.

Dermal cells are capable of initiating contact-hypersensitivity responses but the precise identification of the antigen-presenting cell within murine dermis is lacking. Class II major histocompatibility complex (MHC)+ cells with dendritic shape and lacking endothelial factor VIII but expressing the dendritic antigen-presenting cell marker NLDC-145 were observed in the perivascular and interstitial dermis of BALB/c and C3H/HeN skin. The heterogeneous class II MHC+ cells could be divided into two subsets: each was class II MHC+ CD45+ (bone marrow derived) GR-1- (non-neutrophil/macrophage) CD3- (non T), but one subset was CD11b+ (beta 2 integrin) and the other was CD11b-. Ultrastructural examination of class II MHC+ cells revealed the presence of a Langerhans cell-like/indeterminant cell subset with indented nuclei, dendritic morphology, active cytoplasm, and dense intermediate filaments. Phagolysomes and Birbeck granules were not observed in such cells, indicating these were distinct from dermal macrophages and from classical epidermal Langerhans cells, respectively. Cells with a monocyte/macrophage ultrastructural appearance were also noted, likely representing the class II MHC subset expressing CD11b and Ly6c (monocyte/endothelial antigen). Dermal cells in suspension were capable of processing and presenting large protein antigens to antigen-specific T-cell hybridomas; dermal cells also induced the syngeneic mixed lymphocyte reaction. The dermal antigen-presentation activities were totally abrogated by removal of class II MHC+ cells, but not by removal of CD11b+ cells or Ly6c+ cells, indicating that potent antigen-presenting cell activity was restricted to the class II MHC+ CD11b- Ly6c- subset (Langerhans cell-like/indeterminant cells). In conclusion, within a complex array of dermal leukocytes a murine dermal class II MHC+ cell population expressing a Langerhans cell-like/dendritic antigen-presenting cell phenotype and exhibiting potent antigen processing and presenting activity can be identified. The positioning of potent interstitial dendritic antigen-presenting cells at the interface of the vasculature with the dermal interstitium provides rapid access to an antigen-presenting cell as T cells first egress into the skin.

Animals↗
PubMed1994

High frequency of HLA-DQB1*0301 allele in patients with pure ocular cicatricial pemphigoid.

Two factors, is classification and its immunogenetics, may have contributed to an incomplete understanding of the pathogenic mechanism in the disease group commonly termed 'cicatricial pemphigoid'. We have previously demonstrated that pure ocular cicatricial pemphigoid (OCP) is a unique clinical and immunopathological entity. In an effort to better define the immunogenetic characteristics for patients with pure OCP, we performed HLA typing for the class II MHC gene HLA-DQB1*0301 allele, by amplifying genomic DNA extracted from patients with polymerase chain reaction, followed by hybridization with a sequence-specific oligonucleotide probe on dot-blotted and Southern-blotted amplified DNA samples. Ninety percent (9/10) of patients with pure OCP had the DQB1*0301 allele, in contrast to 52% (17/33) of normal individuals who had the DQB1*0301 allele. The high frequency of the HLA-DQB1*0301 allele in patients with pure OCP may point to a distinct immunogenetic pattern and possibly a distinct pathomechanism for the disease.

Alleles↗
PubMed1993

Flow cytometric identification of proliferative subpopulations within normal human epidermis and the localization of the primary hyperproliferative population in psoriasis.

In this study we define the proliferative compartments of in vivo human epidermis, using specific antibodies related to cell differentiation (beta 1 and beta 4 integrins and K1/K10 differentiation keratins) and cell cycle (proliferating cell nuclear antigen [PCNA]) in combination with flow cytometric quantitation of the DNA content and optical characteristics of the cells. The beta 1 integrin (CD29) marked both of the potentially proliferative subsets in normal epidermis. One subset of normal epidermis is CD29+ K1/K10-, which was predominantly basal, and found to be comprised of slow cycling, small cells with primitive cytoplasmic organization. The vast majority (95.5%) of these cells were in a quiescent state (G0/early G1) as indicated by their lack of the cyclin, PCNA. The other proliferative subset of normal epidermis was CD29+ K1/K10+, which was suprabasal and occasional basal, highly proliferative, larger in size, and which exhibited a more complex cytoplasmic structure. Because early differentiation (K1/K10 expression) has begun in the CD29+ K1/K10+ subset, it is highly likely that they represent the proliferative population which is capable of transiently amplifying itself before terminal differentiation. Within lesional psoriatic epidermis, similar proliferative cell populations were present as in normal epidermis, and the hyperproliferative defect was localized to the beta 1 and beta 4 integrin+, K1/K10- populations, which in normal epidermis is basally located and quiescent with regard to cell cycle. In psoriatic epidermis, a six- to sevenfold increase in the number of cells in the S/G2+M phase of cell cycle was found among CD29+ K1/K10- cells (p < 0.05). Furthermore, all lesional K1/K10- cells showed high PCNA positivity, indicating that all these cells had been recently induced into cell cycle. By contrast, the proportion of cycling cells among lesional psoriatic CD29+ K1/K10+ keratinocytes was similar to normals. Anti-HLA-DR, CD45, and vimentin antibodies were used to concomitantly track the proliferative states of Langerhans cell, melanocyte, and infiltrating leukocyte populations. In normal epidermis, the cycling fractions (cells in S/G2/M phase) of these cells were similar to the CD29+K1/K10- keratinocytes, whereas in lesional epidermis their cycling pools were increased relative to normal, but not so much as the proliferative fractions of psoriatic CD29+ K1/K10- keratinocytes. These data demonstrate the use of simultaneous analysis of integrin expression, differentiation keratins, cyclin, cell cycle status, and optical characteristics of freshly isolated human epidermal cells. Such analysis allowed the physical identification and quantification of cy cling populations in normal human skin, and has enabled the precise location of the primary epidermal proliferative defect in psoriasis.

Antigens, CD↗
PubMed1993

Immune-mediated subepithelial blistering diseases of mucous membranes. Pure ocular cicatricial pemphigoid is a unique clinical and immunopathological entity distinct from bullous pemphigoid and other subsets identified by antigenic specificity of autoantibodies.

BACKGROUND AND DESIGN: There is much confusion in the clinical classification of immune-mediated subepithelial blistering diseases of mucous membranes. We conducted a 6-year comprehensive study to better classify this heterogeneous disease group. Indirect immunofluorescence was performed on a salt-split-skin substrate to detect circulating antibasement membrane antibodies (n = 47). Serologic reactivity against cultured keratinocyte antigens was examined by immunoblots (n = 38) and immunoprecipitation (n = 15). The results were correlated with the clinical features and direct immunofluorescence data of the entire patient group (n = 87) without preassignment of clinical diagnoses. chi 2 Statistical analyses compared these results with those of the classic bullous pemphigoid group (n = 36). RESULTS: When compared with the bullous pemphigoid patients, a subset of patients with combined oral mucosal and skin lesions demonstrated marked similarity in direct and indirect immunofluorescence findings and in serologic reactivity to bullous pemphigoid antigens. By contrast, a subset of patients with only ocular lesions exhibited significantly lower in vivo deposits of IgG and C3, higher deposits of fibrin, virtual absence of circulating antibodies, and negative serologic reactivity to bullous pemphigoid antigens. CONCLUSIONS: Ocular patients without skin or mouth lesions, in particular those with negative indirect immunofluorescence, should be distinctively classified as ocular cicatricial pemphigoid, a unique clinical and immunopathologic entity. Patients with mucous membrane involvement who also demonstrate skin lesions and antibodies to the root of salt-split-skin substrate should be classified as anti-BP Ag mucosal pemphigoid, even though they may exhibit severe oral and/or ocular diseases. The remaining mucous membrane patients are heterogeneous. Some can be classified on the basis of autoantibodies to other basement membrane determinants, or if serum autoantibody negative, on the basis of clinical features (ie, pure oral mucosal pemphigoid or overlapping mucosal involvement).

Autoantibodies↗
PubMed1993

Neutrophils, differentiated macrophages, and monocyte/macrophage antigen presenting cells infiltrate murine epidermis after UV injury.

We asked whether, as in humans, a population of antigen-presenting macrophages infiltrates the epidermis of ultraviolet (UV)-exposed BALB/c mice. Using three-color flow cytometry on cell suspensions plus in situ immunofluorescence microscopy, the phenotype of normal Langerhans cells was class II major histocompatibility complex (MHC+), CD11b+, NLDC-145+, BM8+ CD45+ and homogeneous. By contrast, in epidermal cells harvested 3 d following UV (UV-EC), there were two subsets of class II MHC+ cells: 1) class II MHChi CD11b+, and 2) class II MHClo CD11b-. Neither expressed the Langerhans cell markers BM8 and NLDC-145. In addition, there were two major populations of class II MHC- CD11b+ cells; half of these expressed the GR-1 neutrophil marker. Langerhans and dendritic epidermal T cells were markedly reduced after UV injury. By electron microscopy, immunomagnetic bead-purified CD11b+ cells in UV-EC were comprised of neutrophils, differentiated macrophages, and mononuclear cells with prominent lysosomes, but no Birbeck granules; the class II MHC+ subset resembled a monocytic cell in between differentiated macrophages and indeterminate dendritic cells. Functionally, immediately following in vivo UV exposure, the allogeneic antigen-presenting cell capacity of UV-EC was reduced to 21 +/- 6% of control epidermal cells (C-EC); by 3 d, antigen-presenting cell activity of UV-EC had recovered to 59 +/- 11% of C-EC, although at this time NLDC-145+ Langerhans cells had reached their lowest number. The recovered antigen-presenting cell activity was critically dependent upon the class II MHChiCD11b+ cells. Sensitization of BALB/c mice through skin that contained these antigen-presenting cells (3 d after UV) resulted in tolerance to dinitrofluorobenzene. By contrast, sensitization through UV-exposed skin immediately after the exposure resulted in unresponsiveness without tolerance, demonstrating temporal association of tolerance with leukocytic infiltration. In summary, murine epidermis responds to an acute UV injury in vivo with an initial abrogation of antigen-presenting activity followed by epidermal infiltration with neutrophils, differentiated macrophages, and monocytic antigen-presenting cells that are distinct from Langerhans cells with regard to expression of Langerhans cell markers and ultrastructure.

Animals↗
PubMed1993

Identification and partial characterization of a novel 105-kDalton lower lamina lucida autoantigen associated with a novel immune-mediated subepidermal blistering disease.

Certain skin basement membrane components, such as bullous pemphigoid antigens and epidermolysis bullosa acquisita antigen, were discovered as a result of an autoimmune reaction. In this report, we describe a unique lamina lucida determinant associated with a novel immune-mediated subepidermal bullous dermatosis. This unique bullous dermatosis resembled severe toxic epidermal necrolysis clinically. The histologic findings resemble dermatitis herpetiformis. Direct immunofluorescence microscopy detected linear immunoglobulin G (IgG) and C3 deposition at the cutaneous basement membrane zone of lesional and perilesional skin. Direct and indirect immunoelectron microscopy localized the IgG deposits to the lowest portion of the lamina lucida. The patient's autoantibodies, belonging to the IgG1 subclass, labeled basement membrane zone of normal intact human skin, oral mucosa, and conjunctiva, and localized to the dermal side of salt-split normal adult and neonatal human skin, but failed to react with human fetal skin up to 142 gestational days. The patient's autoantibodies failed to react with bullous pemphigoid antigens or epidermolysis bullosa acquisita antigen (type VII collagen) by immunoblotting. Instead, the patient's autoantibodies unequivocally labeled a 105-kilodalton (kD) protein in cellular extracts and conditioned media of human cultured keratinocytes and dermal fibroblasts. The titer of the patient's antibody against the cutaneous basement membrane zone and the intensity of the antibody reactivity against the 105-kD protein paralleled the patient's disease activity. Thus, this 105-kD lower lamina lucida protein represents a novel autoantigen and this patient's disease represents a novel autoantigen and this patient's disease represents a deep lamina lucida pemphigoid, distinguishable from all other known autoimmune bullous dermatoses.

Autoantigens↗
PubMed1993

Cyclosporin A rapidly inhibits epidermal cytokine expression in psoriasis lesions, but not in cytokine-stimulated cultured keratinocytes.

To better understand the cellular target(s) of cyclosporin action in psoriasis, we have studied the effects of systemic short-term (7 d), low-dose (3-7.5 mg/kg) cyclosporin A administration on the expression of the cytokines interleukin (IL)-8 and IL-1 beta in psoriatic lesions. RNA blot hybridization analysis of pretreatment keratome biopsies revealed that expression of both cytokine mRNAs was highly variable from patient to patient. Significant covariation of both cytokine mRNA levels was noted (r = 0.86, p < 0.0001). However, there was no significant correlation between expression of either cytokine and clinical severity, as measured by the pretreatment Psoriasis Area and Severity Index (PASI). IL-1 beta protein levels measured by enzyme-linked immunosorbent assay (ELISA) were highly correlated with IL-1 beta mRNA levels, indicating that the differences in transcript levels accurately reflect differences in epidermal cytokine protein. Significant reductions in both cytokine transcripts and in IL-1 beta immunoreactive protein were noted in the high expression subgroup after 1 week of cyclosporin A therapy, prior to detectable clinical improvement. In contrast to its pronounced effects on epidermal cytokine expression in vivo and the allogeneic mixed lymphocyte reaction in vitro, cyclosporine A did not inhibit the induction of intercellular adhesion molecule (ICAM)-1 or IL-8 mRNAs by cultured keratinocytes in response to IL-1 beta or the combination of tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma. These data suggest that epidermal keratinocytes respond to signals produced by activated T cells by coordinate expression of multiple cytokines, and that cyclosporin A acts primarily through blockade of T cells, rather than through keratinocyte activation.

Blotting, Northern↗
PubMed1992

Retinoic acid and phorbol ester synergistically up-regulate IL-8 expression and specifically modulate protein kinase C-epsilon in human skin fibroblasts.

Phorbol ester (TPA) and retinoic acid (RA) are two potent immunomodulatory agents whose actions are mediated through distinct signal transduction pathways involving protein kinase C (PKC) and nuclear RA receptors, respectively. We have investigated the interactions between these two pathways in the regulation of expression of the inflammatory cytokine IL-8 in human skin fibroblasts. TPA (as previously reported) and RA both induced IL-8 mRNA and protein in a time- and dose-dependent manner. IL-8 mRNA induction by TPA (10 nM) was maximal (15-fold) within 6 h, and returned to baseline within 24 h of treatment, although maximal induction (10-fold) by RA (1 microM) did not occur until 24 h posttreatment. Induction of IL-8 by TPA was blocked by 1-(5-isoquinolinyl-sulfonyl)-2-methylpiperazine, which inhibits PKC and cAMP-dependent protein kinases (PKA), but not by N-(2-ganidinoethyl)-5-isoquinoline sulfonamide, which preferentially inhibits PKA, consistent with the participation of PKC in the induction of IL-8 by TPA. In contrast, induction of IL-8 by RA was inhibited by both 1-(5-isoquinoline sulfonamide and N-(2-gamidinoethyl)-5-isoquinoline sulfonamide, suggesting the participation of PKA in the induction of IL-8 by RA. However, activation of PKA by addition of cAMP analogues was not sufficient to induce IL-8 expression. Induction of IL-8 by RA also did not appear to be mediated indirectly through induction of IL-1, because addition of IL-1R antagonist did not block IL-8 induction by RA. RA and TPA added in combination synergistically enhanced expression of IL-8 mRNA, measured at 6 (2-fold) and 24 h (10-fold) posttreatment. To investigate the mechanism of this synergy, the effect of TPA and RA on fibroblast PKC activation and PKC isozyme levels were determined. TPA, either alone or together with RA, but not RA alone, stimulated phosphorylation of an endogenous 80-kDa PKC substrate. Dermal fibroblasts expressed three PKC isozymes (alpha, (delta, and (epsilon). TPA, but not RA, down-regulated PKC-alpha, neither TPA or RA affected the level of PKC-delta, and both TPA and RA down-regulated PKC-epsilon. This latter effect was enhanced 2-fold by addition of RA and TPA together. These data suggest that modulation of PKC-epsilon may be a common participant in the regulation of IL-8 expression by TPA and RA.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1992

Psoriatic skin reveals the in vivo presence of an epidermal IL-1 inhibitor.

Production of inhibitor(s) of IL-1 activity can be induced in keratinocytes by exposure to UVB. We describe in this study the characterization of an endogenous constitutively expressed IL-1 inhibitor which is present in extracts of human psoriatic epidermal keratome biopsies. Size-fractionated extracts of normal human epidermis did not reveal IL-1 inhibitory factor(s) activity in normal epidermis. Psoriatic epidermal extracts, however, contained virtually no IL-1 bioactivity and inhibited the activity of recombinant human IL-1 beta. This IL-1 inhibitor has a molecular weight of approximately 30 kDa and a pI of 5.3, as revealed by fast protein liquid chromatography size fractionation and chromatofocusing of psoriatic epidermal extracts. IL-1 inhibitory activity was not blocked by neutralizing anti-TGF beta monoclonal antibody. It did not have any inhibitory effect upon normal cellular proliferation but could block the IL-1 induction of IL-2 production by LBRM.33 cells as late as 4 h after exposure of LBRM.33 cells to IL-1. Thus, in vivo human psoriatic epidermis expresses an IL-1 inhibitor that specifically inhibits IL-1 activity but which appears distinct from previously described UV-induced epidermal IL-1 inhibitory activity or TGF beta.

Biopsy↗
PubMed1992

Human dermal fibroblast interleukin-1 receptor antagonist (IL-1ra) and interleukin-1 beta (IL-1 beta) mRNA and protein are co-stimulated by phorbol ester: implication for a homeostatic mechanism.

Although the major functions of fibroblasts are to produce extracellular matrix and to maintain a structural framework for organ systems, recent studies have demonstrated that fibroblasts are active participants in inflammatory processes by synthesizing various inflammatory mediators. In this report, we provide evidence that fibroblasts may contribute to the regulation of inflammation by the synthesis of both the intracellular form and the secretory form of interleukin-1 receptor antagonists in conjunction with interleukin-1 beta production. Indirect immunofluorescence microscopy localized interleukin-1 receptor antagonist and interleukin-1 beta proteins primarily in the fibroblast cytoplasm. Polymerase chain reaction amplification of reverse-transcribed mRNA with primers specific for the intracellular form of interleukin-1 receptor antagonist detected cDNA fragments present in both unstimulated and phorbol ester-stimulated fibroblasts, identical in molecular size to that in unstimulated keratinocytes. Amplification with primers specific for the secretory form of interleukin-1 receptor antagonist, however, detected cDNA fragments in phorbol ester-stimulated fibroblasts and phytohemagglutinin-stimulated peripheral mononuclear cells, but not in unstimulated fibroblasts or keratinocytes. The amplified fibroblast cDNA sequences for both intracellular and secretory interleukin-1 receptor antagonists were confirmed by digestion with three restriction endonucleases. By ethidium bromide visualization of amplified cDNA derived from serially diluted total cellular RNA and by Southern blot hybridization analysis of amplified cDNA, we have demonstrated that fibroblast interleukin-1 receptor antagonist mRNA and interleukin-1 beta mRNA were co-stimulated by phorbol ester. Similarly, ELISA demonstrated that fibroblast cytoplasmic interleukin-1 receptor antagonist protein and interleukin-1 beta protein were co-stimulated by phorbol ester. Our data suggests that the intracellular form of interleukin-1 receptor antagonist may be important in maintaining physiologic homeostasis in fibroblasts during interleukin-1 beta induction and release.

Base Sequence↗
PubMed1992

Interleukin-1 receptor antagonist in normal and psoriatic epidermis.

The objective of these studies was to characterize the IL-1 inhibitory activity present in normal and psoriatic epidermis from clinically stable lesions. Fractionation of normal epidermal cytosol on a molecular sizing column failed to reveal the presence of IL-1 inhibitory bioactivity. However, specific ELISAs indicated that both the IL-1 receptor antagonist (IL-1ra) and IL-1 alpha were present in overlapping peaks. Further fractionation of the normal epidermal cytosol by anion exchange chromatography separated these two molecules, revealing the IL-1 inhibitory bioactivity of the IL-1ra molecule. Similar studies on psoriatic epidermal cytosol indicated the presence of IL-1 inhibitory bioactivity and IL-1ra protein. The IL-1 inhibitory bioactivity of both normal and psoriatic cytosol was neutralized by a mAb specific for IL-1ra. The ratio of IL-1ra to IL-1 alpha proteins was significantly increased in involved psoriatic skin compared with normal skin. By Western blot analysis this IL-1ra was approximately 20 kD, slightly larger than monocyte-derived IL-1ra and equivalent to an intracellular variant of IL-1ra expressed by keratinocytes. Polymerase chain reaction indicated the presence of mRNA for both forms of IL-1ra in normal epidermis, with both forms increased in psoriatic-involved skin. Immunofluorescence studies revealed the IL-1ra protein to be concentrated in the stratum granulosum of normal skin and in the basal-midbasal layers of psoriatic epidermis. These results suggest that the balance between intracellular IL-1ra and IL-1 alpha may be an important influence on keratinocyte growth and/or differentiation, as well as on the inflammatory potential of IL-1 in injured skin.

Antibodies, Monoclonal↗
PubMed1992

T-cell activation is potentiated by cytokines released by lesional psoriatic, but not normal, epidermis.

BACKGROUND AND DESIGN: T-cell activation appears to be critical for the maintenance of psoriatic lesions. In this study, we determined whether cytokines released by epidermal cells from psoriatic lesions are providing signals that result in propagation of intralesional T-cell activation. Supernatants were obtained from epidermal cell cultures derived from skin biopsy specimens of psoriatic patients and normal subjects. These supernatants were added to purified normal CD4+ T cells activated via T-cell receptor (immobilized anti-CD3 and fibronectin) or via other activating pathways (anti-CDw60 or UM4D4). RESULTS: Psoriatic supernatants (n = 9), but not normal supernatants (n = 7, P < .0006), potentiated T-cell stimulation with anti-CD3 and fibronectin to 172% +/- 41% over control stimulation levels. The degree of lesional psoriatic epidermal cell potentiation correlated with the clinical severity of the lesion (r = .82, P = .007). Psoriatic epidermal cytokine potentiation of T-cell activation was not limited to T-cell receptor mediated stimulation; potentiation of anti-CDw60-stimulated CD4+ T cells was also observed. Neutralizing antisera to interleukin 1 and interleukin 8, but not interleukin 6, were found to reduce only partly the observed potentiation of T-cell activation. To determine whether cyclosporine is down modulating T-cell-potentiating cytokine activity in psoriasis, we compared samples obtained during a double-blind clinical trial of intralesional cyclosporine. T-cell-potentiating activity from psoriatic lesional sites treated with cyclosporine was not significantly modulated relative to the activity derived from vehicle-treated or untreated sites. CONCLUSION: These data demonstrate that lesional psoriatic epidermal cells release a balance of cytokines that potentiate T-cell activation. Because normal epidermal cells do not potentiate T-cell activation in this system, these findings demonstrate a mechanism by which the epidermis may non-specifically potentiate and perpetuate T-cell activation in psoriatic lesions.

CD4-Positive T-Lymphocytes↗
PubMed1991

Hyperstimulatory CD1a+CD1b+CD36+ Langerhans cells are responsible for increased autologous T lymphocyte reactivity to lesional epidermal cells of patients with atopic dermatitis.

We studied whether abnormalities in epidermal APC could be responsible for intracutaneous T cell activation in atopic dermatitis (AD). In the absence of added Ag, patients' peripheral blood T cells demonstrated significantly increased proliferation to their autologous lesional epidermal cells (mean +/- SEM = 19,726 +/- 9,754 cpm [3H]TdR uptake) relative to epidermal cells from uninvolved AD skin (2179 +/- 697 cpm) (n = 10) (p = 0.0001, log transformed data). AD T cell proliferative responses to autologous epidermal cells were dependent upon cells expressing HLA-DR, CD1a, and CD36, and not upon keratinocytes or their cytokines. Ultrastructurally, these cells ranged from typical Langerhans cells to indeterminate cells with irregular nuclear contours. Enriched populations of lesional AD Langerhans cells were highly stimulatory for autologous T cells, whereas equal numbers of Langerhans cells from non atopic epidermis were poor stimulators, even at high concentrations. The dermal perivascular dendritic cell markers CD36 and CD1b, not usually present on normal epidermal APC, were expressed by 40 and 60% of lesional AD CD1a+ epidermal Langerhans cells, respectively. Addition of anti-CD1b to cocultures of AD epidermal cells and autologous T lymphocytes augmented T cell activation, suggesting that the expression of CD1b by AD Langerhans cells may represent over expression of a molecule functionally linked to the enhanced T cell stimulatory capacity of these cells. Thus, stimulatory signals for T cells contained within AD epidermis are carried by cells in an abnormal differentiation state as indicated by expression of phenotypic characteristics of both epidermal and dermal antigen presenting cells (HLA-DR+, CD1a+, CD1b+, CD36+). We propose that activation of autologous T cells by an altered cutaneous APC population may represent a mechanism for the hyperactive and disordered cell-mediated immune response that characterizes the dermatitic lesions of AD.

Antigen-Presenting Cells↗
PubMed1991

Ocular cicatricial pemphigoid occurring as a sequela of Stevens-Johnson syndrome.

Ocular cicatricial pemphigoid is a chronic scarring inflammation of the ocular mucosae that can lead to blindness. Although cicatricial pemphigoid has been classified clinically, histopathologically, and immunopathologically, no definite initiating factor or precipitating factor has been identified. In this report, we describe five cases of ocular cicatricial pemphigoid that developed following an acute episode of severe ocular inflammatory injury secondary to Stevens-Johnson syndrome. The time lag between the onset of Stevens-Johnson syndrome and cicatricial pemphigoid ranged from a few months to 31 years. All five patients had linear immune deposits characteristic of cicatricial pemphigoid along the basement membrane zone of mucosal biopsy specimens as detected by either direct immunofluorescence microscopy or direct immunoperoxidase staining. In two patients whose serum was tested, a Western blot assay taken of keratinocyte antigens that had undergone electrophoresis reacted with the serum and identified a 120-kd epidermal antigen detected by the IgG class antibodies. All five patients were treated with systemic immunosuppressive therapy for cicatricial pemphigoid, and we obtained objective responses. Severe ocular mucosal injury such as that which occurs in Stevens-Johnson syndrome may be a precipitating factor in the development of ocular cicatricial pemphigoid.

Adult↗
PubMed1991

cDNA cloning of an intracellular form of the human interleukin 1 receptor antagonist associated with epithelium.

A cDNA encoding a receptor antagonist of interleukin 1 (IL-1ra), secreted from human monocytes, has recently been isolated and sequenced [Eisenberg, S. P., Evans, R. J., Arend, W. P., Verderber, E., Brewer, M. T., Hannum, C. H. & Thompson, R. C. (1990) Nature (London) 343, 341-346]. We have identified another version of this IL-1ra, which is predominantly expressed in epithelial cells. This IL-1ra lacks a leader sequence and, thus, is probably intracellular. Both proteins are derived from the same gene through use of an alternative transcriptional start site and internal splice-acceptor site. Expression of intracellular IL-1ra cDNA in COS cells demonstrated that the intracellular product specifically inhibited exogenous interleukin 1-dependent responses. Keratinocytes were shown to contain significant amounts of nonsecreted IL-1ra protein. Constitutive expression of the intracellular IL-1ra may be an intracellular defensive mechanism in exposed epithelial cells and/or may serve to regulate autocrine interleukin 1-mediated pathways of differentiation.

Amino Acid Sequence↗
PubMed1991

Cellular, immunologic and biochemical characterization of topical retinoic acid-treated human skin.

Histologic and clinical improvement of sun-exposed skin following topical treatment with retinoic acid has been reported. Daily application of retinoic acid typically results within 2-5 d in an erythematous scaling reaction, which lessens with continued usage. The cellular, immunologic, and biochemical basis of this retinoid reaction and its role in the repair of photodamaged skin are not known. To investigate the retinoid reaction in man, we have treated non-sun-exposed skin with 0.1% retinoic acid cream (Retin-A, Ortho Pharmaceutical Corporation, Raritan, NJ) under occlusion for 4 d to induce erythema and then examined changes in 1) histology, 2) expression of cell-surface molecules, 3) the enzymes and second messengers of the phospholipase C/protein kinase C signal-transduction system, 4) levels of eicosanoids, and 5) levels of interleukin-1 protein and mRNA. These parameters were chosen for measurement both because they are indicators of epidermal function and previous studies suggest they may be responsive to retinoic acid treatment. Epidermal cell growth as judged by increased epidermal thickness and mitotic figures was significantly increased in retinoic acid-treated skin compared to vehicle-treated controls. Increased numbers of CD4+ T cells accompanied by prominence of dermal dendrocytes in the papillary dermis and focal keratinocyte expression of intercellular adhesion molecule-1 were observed in retinoic acid-treated biopsies. Phosphoinositide-specific phospholipase C activity and 1,2-diacylglycerol content were also elevated in retinoic acid-treated epidermis. Protein kinase C activity was reduced by one third in both the soluble and membrane fraction, suggesting down-regulation. Surprisingly, in view of the inflammatory nature of the retinoid reaction, no increases were observed in arachidonic acid, its metabolites, interleukin-1 alpha, or interleukin-1 beta. To examine the specificity of the retinoid reaction, subjects were treated with the irritant sodium lauryl sulfate, under conditions that resulted in a reaction clinically similar to that observed with retinoic acid. The histologic alterations induced by sodium lauryl sulfate were found to be indistinguishable from those induced by retinoic acid. These data indicate that, although a wide range of cellular and molecular alterations occur in retinoic acid-treated skin, these changes may not be necessarily specific or unique for retinoic acid.

Cell Adhesion Molecules↗
PubMed1991

Elevated thymidine phosphorylase activity in psoriatic lesions accounts for the apparent presence of an epidermal "growth inhibitor," but is not in itself growth inhibitory.

An apparent tissue-specific growth inhibitor, or chalone, obtained from psoriatic lesions was tentatively identified in the 100-kDa fraction based upon inhibition of DNA synthesis, as measured by [3H]-thymidine uptake by a squamous cell carcinoma cell line, SCC 38. This fraction, however, failed to inhibit SCC 38 cell growth when assessed directly in a neutral red uptake assay. Characterization of the inhibitor of [3H]-thymidine uptake revealed it to have biochemical properties identical to thymidine phosphorylase: 1) molecular weight close to 100 kDa, 2) isoelectric point of 4.2, and 3) thymidine phosphorylase enzyme activity. Thus, we conclude that its ability to inhibit [3H]-thymidine uptake was due to thymidine catabolism rather than inhibition of DNA synthesis or growth inhibition. Examination of thymidine phosphorylase activity in keratome biopsies from psoriatic and normal skin demonstrated a twentyfold increase in activity in psoriatic lesions relative to non-lesional or normal skin. This increase in metabolism of thymidine was due to thymidine phosphorylase rather than uridine phosphorylase activity. The correlation between increased thymidine phosphorylase activity and increased keratinocyte proliferation in vitro (cultured) and in vivo (psoriasis), suggests that this enzyme may play a critical role in providing the thymidine necessary for keratinocyte proliferation.

Biopsy↗